If I get it brand new, and initiate it with a lower version of itunes, will it work then?
It should. That's what I did with mine using iTunes 9.2.1
Or do I even have to initiate it with itunes in the first place?
Yes. Once. Just make sure you don't allow iTunes to sync anything to the device. Specifically under Device \ Summary \ Options make sure there's a check mark in the box Manually manage music and videos. And under Music, there is
no check mark next to Sync Music.
What happens if I accidentally initiate it with iTunes 11... Can I undo that?
Yes. Using the older version of iTunes do a Restore under Device \ Summary. Although I don't see how one can accidentally initiate it with iTunes 11 unless you have both versions installed, which I don't think you can do.
The only other thing I can add, is that if you're buying the iPod brand new, get it from a place where it can be returned if it doesn't work as expected.
Good luck.